As taught by Henkel et al U.S. Pat. No. 1,108,752 at temperatures generally below the ordinary ignition point of hydrogen, palladium is a catalyst promoting the formation of both hydrogen perioxide and water. Such synthesis of hydrogen peroxide from the elements has aroused interest, leading to disclosures such as Hooper U.S. Pat. No. 3,336,112, Hooper U.S. Pat. No. 3,361,533 and Kim et al U.S. Pat. No. 4,007,256. It has been the standard practice of prior art technologists to prepare a mixture of gaseous oxygen and gaseous hydrogen for introduction to the synthesis catalyst. Such gaseous mixtures of hydrogen and oxygen are of an explosive nature. To the extent that a catalyst becomes deactivated and/or to the extent that the explosive gaseous mixture permeates into zones other than those initially intended, certain safety hazards have been recognized in connection with Henkel-tupe synthesis of hydrogen peroxide. There have been many situations in which the market price for hydrogen peroxide was significantly greater than the local market price for either hydrogen or oxygen. Accordingly, there has been a long standing demand for a more satisfactory method of synthesizing hydrogen peroxide from its elements.